Present status of sentinel lymph node biopsy in cervical cancer

Cervical cancer is the fourth most common cancer in women, and seventh overall. This disease represents a medical, economic and social burden. In early FIGO stage patients (IA, IB1 and IIA1), nodal involvement is the most important prognostic factor. Imaging evaluation of nodal metastasis is of limited value. In order to determine lymph node involvement, allow loco-regional control of the disease, define the need for adjuvant radiotherapy and improve survival, standard surgery for early disease is radical hysterectomy with systematic pelvic lymphadenectomy. However, this surgical treatment has risks and complications: longer operative time, larger blood loss, neurovascular or ureteral injury, lower-limb lymphedema, symptomatic lymphocysts, hydronephrosis. A method that allows to define the presence of regional metastasis with less morbidity and equal or greater precision is particularly relevant. The use of the sentinel lymph node biopsy is intended to reach that purpose. The present study reviews recent literature on the role of sentinel lymph node biopsy in cervical cancer, analyzing its indications and contraindications, injection and detection techniques, tracers used, surgical and pathological approaches and its applicability in up-to-date clinical practice.     

Trophic interactions of Antarctic seals as determined by stable isotope signatures

The diets and trophic interactions among Weddell, crabeater, Ross, and leopard seals in the eastern Ross Sea, Antarctica, were investigated by the use of stable isotope techniques during the 1999–2000 summer seasons. The ¹³C and ¹⁵N values in seal serum clearly distinguished the three Antarctic pack-ice seal species at different trophic positions (Weddell>Ross>crabeater). These patterns appeared to reflect a close linkage to their known foraging ecology and diving behaviors, and agreed well with their presumed dietary diversity. The more enriched ¹³C and ¹⁵N values in male Weddell seals than those in females suggested differences in foraging preferences between them. Significant differences in ¹⁵N were also found among different age groups of Weddell seals. A strong correlation between the C:N ratios and serum cholesterol was probably due to extremely high cholesterol levels in phocids. Comparisons of isotope data with harbor seals revealed distinct differences between Antarctic phocids and the northern seal species.     

Assessment of lymph node status in gallbladder cancer: location, number, or ratio of positive nodes

ABSTRACT: BACKGROUND: Assessment of lymph node status is a critical issue in the surgical management of gallbladder cancer. The aim of this study was to compare the anatomical location of positive nodes, number of positive nodes, and lymph node ratio (LNR) as prognostic predictors in gallbladder cancer. METHODS: We conducted a retrospective analysis of 135 patients with gallbladder cancer who underwent a radical resection with regional lymphadenectomy. A total of 2,245 regional lymph nodes were retrieved (median, 14 per patient). The location of positive nodes was classified according to the AJCC staging manual (7th edition). 'Optimal' cutoff values were determined for the number of positive nodes and LNR based on maximal chi 2 scores calculated with the Cox proportional hazards regression model. RESULTS: Lymph node metastasis was found histologically in 59 (44%) patients. The 'optimal' cutoff values for the number of positive nodes and LNR were determined to be three nodes and 10%, respectively. Univariate analysis identified location of positive nodes (pN0, pN1, pN2; P < 0.001), number of positive nodes (0, 1 to 3, [greater than or equal to]4; P < 0.001), and LNR (0%, 0 to 10%, >10%; P < 0.001) as significant prognostic factors. Multivariate analysis identified number of positive nodes as an independent prognostic factor (P = 0.004); however, location of positive nodes and LNR failed to remain as an independent variable. CONCLUSIONS: The number of positive lymph nodes better predicts patient outcome after resection than either the location of positive lymph nodes or LNR in gallbladder cancer. Dividing the number of positive lymph nodes into three categories (0, 1 to 3, or [greater than or equal to]4) is valid for stratifying patients based on the prognosis after resection.     

Diagnostic accuracy of tests for lymph node status in primary cervical cancer: a systematic review and meta-analysis

Background

Lymph node status is the key to determining the prognosis and treatment of cervical cancer. However, it cannot be assessed clinically, and testing for nodal metastasis is controversial. We sought to systematically review the diagnostic accuracy literature on sentinel node biopsy, positron emission tomography, magnetic resonance imaging and computed tomography to evaluate the accuracy of each index test in determining lymph node status in patients with cervical cancer.

Methods

We searched MEDLINE (1966–2006), EMBASE (1980–2006), Medion (1980–2006) and the Cochrane library (Issue 2, 2006) for relevant articles. We also manually searched the reference lists from primary articles and reviews, and we contacted experts in the field for conference abstracts and unpublished studies. We performed random-effects meta-analysis of accuracy indices, and we performed meta-regression analysis to test the effect of study quality on diagnostic accuracy and to identify other sources of heterogeneity.

Results

We included 72 relevant primary studies, involving a total of 5042 women, in our analysis. We found that, in determining lymph node status, sentinel node biopsy had a pooled positive likelihood ratio of 40.8 (95% confidence interval [CI] 24.6–67.6) and a pooled negative likelihood ratio of 0.18 (95% CI 0.14–0.24). The pooled positive likelihood ratios (and 95% CI) were 15.3 (7.9–29.6) for positron emission tomography, 6.4 (4.9–8.3) for magnetic resonance imaging and 4.3 (3.0–6.2) for computed tomography. The pooled negative likelihood ratios (and 95% CIs) were 0.27 (0.11–0.66) for positron emission tomography, 0.50 (0.39–0.64) for magnetic resonance imaging and 0.58 (0.48–0.70) for computed tomography. Using a 27% pretest probability of lymph node metastasis among all cases (regardless of stage), we found that a positive sentinel node biopsy result increased post-test probability to 94% (95% CI 90%–96%), whereas a positive finding on positron emission tomography increased it to 85% (75%–92%).

Interpretation

Sentinel node biopsy has greater accuracy in determining lymph node status among women with primary cervical cancer than current commonly used imaging methods.In the United States and European Union it is estimated that cervical cancer is diagnosed in about 42 000 women each year.^1,2 The International Federation of Gynecology and Obstetrics criteria currently used to stage cervical cancer do not account for lymph node involvement, but the lymphatic spread of the disease is key to determining prognosis and appropriate treatment.The primary treatment options for early cervical cancer (stage 1B1 or less advanced) are surgery and chemoradiotherapy, which have similar survival rates.³ Surgical treatment offers some degree of fertility preservation and may not have the long-term complications associated with chemoradiotherapy. However, because it is not possible to clinically detect pelvic and para-aortic lymph node metastasis, surgery typically includes lymphadenectomy, which may reveal metastatic spread. In such cases, chemoradiotherapy is required, which would make the initial surgical procedure unnecessary in retrospect. There has been considerable interest in using a preoperative, noninvasive test to determine lymph node status in order to select the most appropriate treatment option. Such a test could avoid unnecessary surgical intervention, reduce morbidity and correctly direct choice of treatment.In recent years, the use of magnetic resonance imaging and computed tomography to determine lymph node status has increased; however, neither method has been formally included as part of International Federation of Gynecology and Obstetrics staging of cervical cancer. Sentinel node biopsy and positron emission tomography have emerged as competitors to magnetic resonance imaging and computed tomography. The accuracy of magnetic resonance imaging, computed tomography and positron emission tomography has been assessed previously in reviews,^4–6 but updates are required because recent studies have reported on their diagnostic accuracy⁷ and on quality assessment in diagnostic reviews.⁸ Given this background, we performed a systematic review of the literature to compare the accuracy of these 4 methods in determining lymph node status in patients with cervical cancer.